The long-term objective of this research is to develop a safe and efficacious pharmacologic agent for the treatment of respiratory syncytial virus (RSV) infection. RSV is the most common cause of respiratory tract infection in infants and children in the United States. RSV associated infections result in up to 126,000 hospitalizations and more than 500 deaths in infants and small children each year. RSV infections are also a considerable cause of mortality and morbidity in the elderly and immunocompromised individuals. Ribavirin, the only FDA-approved drug for the treatment of severe RSV infections, has questionable efficacy and is difficult and costly for hospital intensive care staff to administer. The Kucera Pharmaceutical Company has identified a novel pharmacologic agent (KPC-15) with potent in vitro activity against RSV. This small molecular weight compound (m.w. < 500) is active against RSV and has little toxicity against normal host cells in vitro. These exciting results warrant further investigation of this compound. The aims of this project are to synthesize KPC-15 and to complete key in vitro and in vivo studies. The activity of KPC- 15 will be evaluated in an animal model of RSV infection (cotton rat) to determine its activity in vivo.